There has recently been an entry key for unlocking or locking doors of a vehicle. The entry key includes a built-in wireless transmission circuit and transmission antenna for wirelessly transmitting an unlocking signal or locking signal unique to the vehicle, so that the doors can be unlocked or locked even from a position away from the vehicle. By simply approaching the vehicle to drive and pressing down an unlocking switch of the entry key to transmit the unlocking signal from the transmission antenna, the driver can open the doors of the vehicle and get into the vehicle.
This type of entry key is used only for remote operations to unlock and lock the doors. To operate various controlled apparatuses installed in the vehicle such as a car navigation apparatus, an audio apparatus, and a side mirror angle adjustment apparatus, the driver makes input operations on input operation keys of input devices provided for the respective controlled apparatuses. The input devices are installed on a center console near the driver's seat, a front instrumental panel, and the like in order for a driver to make input operations. The installation of a large number of input operation keys corresponding to different types of controlled apparatuses around the driver's seat damages the appearance of the interior of the vehicle. In addition, the driver's arms can accidentally touch the input devices to cause a malfunction during driving or a hindrance to driving operations.
There has been known an input device for controlling an operation of various electronic devices of a vehicle, the input device itself being accommodated in a casing attached to inside a steering wheel so that the driver can easily make input operations even during driving without the driver's arms touching the input device (Patent Literature 1).
There has also been known an input device in which the entry key for making remote operations to unlock and lock the doors has additional control functions for controlling an operation of controlled apparatuses in a vehicle, such as opening and closing a window and tuning a radio (Patent Literature 2).